why does colcon build test packages even if -DBUILD_TESTING=OFF is passed about colcon-core HOT 4 OPEN

Setting -DBUILD_TESTING=OFF would prevent CMake from building anything inside:

if (BUILD_TESTING)
   # Testing code
endif()

colcon build is a utility to help you build your package in your workspace in order, using information purely from package.xml, it won't consider anything passed by the cmake-args (and it doesn't make sense to).

You should be able to use --packages-skip ament_cmake_test ament_cmake_gtest to achieve what you want.

I'm not sure if there is a colcon flag that skips all "test_depend" dependencies without explicitly listing them, but if there isn't one that would sound like a good addition to colcon-core to me.

from colcon-core.

I'm not sure if there is a colcon flag that skips all "test_depend" dependencies without explicitly listing them, but if there isn't one that would sound like a good addition to colcon-core to me.

Colcon's package discovery crushes down test depends to be build depends currently; it would be a pretty major design shift for colcon to begin recognizing tests more explicitly.

from colcon-core.

Colcon's package discovery crushes down test depends to be build depends currently; it would be a pretty major design shift for colcon to begin recognizing tests more explicitly.

I'm not sure this is accurate. Part of the issue is that not all package formats support discriminating between dependency types at all, and some just lack consistency in how to do it (looking at you, Python).

For example, for packages which use package.xml, the test dependencies are already enumerated separately. The issue is that the build verb implicitly considers all enumerated dependencies, regardless of type, to be build-time dependencies of the package:

from colcon-core.

a colcon flag that skips all "test_depend" dependencies without explicitly listing them

@ijnek I think this is exactly what I was looking for. Another way might be to prepend

if (BUILD_TESTING)
# CMakeLists content of the test package
endif()

to all test packages?

from colcon-core.